Characterization of protein phosphatases in mouse oocytes.
Characterization of protein phosphatases in mouse oocytes.
复制标题
小鼠卵母细胞中蛋白磷酸酶的表征。
DOI：
10.1006/dbio.1998.9043
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发表时间：
1998
影响因子：
2.7
通讯作者：
Wolf,DP
中科院分区：
文献类型：
--
作者：
Smith,GD;Sadhu,A;Mathies,S;Wolf,DP
冈田酸（OA）促进小鼠卵母细胞减数分裂的恢复，表明丝氨酸/苏氨酸蛋白磷酸酶-1（PP 1）和/或PP 2A参与。然而，在小鼠卵母细胞中的PP 1和/或PP 2A的特异性鉴定尚未报道。在这里，我们证明了完全生长的GVI小鼠卵母细胞含有对应于两种同种型PP 1，PP 1 α和PP 1 γ的mRNA。此外，还存在PP 2A的转录本。在蛋白质水平，通过Western印迹分析，在完全生长的GVI卵母细胞中仅识别PP 1 α和PP 2A。PP 1 γ剪接变异体蛋白PP 1 γ 1和PP 1 γ2均未检测到。促性腺激素刺激的成年小鼠卵巢组织的免疫组织化学分析显示，在卵泡发生的所有阶段的卵母细胞中，PP 1 α和PP 2A均存在亚细胞定位，但PP 1 γ没有。在原始卵母细胞中，PP 1 α和PP 2A存在于细胞质中。在卵子发生的更高级阶段，PP 1 α虽然仍然存在于细胞质中，但高度集中在细胞核中，而PP 2A主要存在于细胞质中，细胞核面积明显减少。PP 1 α和PP 2A在青春期前的卵母细胞中均可检测到。11日龄的小鼠卵母细胞，被认为是OA不敏感和生殖囊泡破裂（GVB）无能，显示PP 1 α和PP 2A主要在细胞质中。到15日龄时，小鼠卵母细胞开始获得OA敏感性和GVB能力，PP 1 α重新定位到核质中，而PP 2A主要保持在胞质中。这是首次在小鼠卵母细胞中特异性鉴定出PP 1 α和PP 2A。PP 1 α和PP 2A的差异定位，以及PP 1 α在减数分裂能力获得过程中的重新定位，表明这些PPs在减数分裂恢复过程中具有不同的调节作用。
Okadaic acid (OA) enhances the resumption of meiosis in mouse oocytes, indicating that serine/threonine protein phosphatase-1 (PP1) and/or PP2A is involved. However, specific identification of PP1 and/or PP2A in mouse oocytes has not been reported. Here we demonstrate that fully grown germinal vesicle-intact (GVI) mouse oocytes contain mRNA corresponding to two isotypes of PP1, PP1αand PP1γ. In addition, the transcript for PP2A was also present. At the protein level only PP1αand PP2A were recognized in fully grown GVI oocytes by Western blot analysis. Neither of the PP1γspliced variant proteins, PP1γ1and PP1γ2, was detectable. Immunohistochemical analysis of ovarian tissue from gonadotropin-stimulated adult mice resulted in subcellular localization of both PP1αand PP2A, but not PP1γ, in oocytes from all stages of folliculogenesis. In primordial oocytes, PP1αand PP2A were present in the cytoplasm. In more advanced stages of oogenesis, PP1α, although still present in the cytoplasm, was highly concentrated in the nucleus, whereas PP2A was predominantly cytoplasmic with a distinct reduction in the nuclear area. Both PP1αand PP2A were immunodetectable in oocytes during the prepubertal period. Eleven-day-old mouse oocytes, considered OA-insensitive and germinal vesicle breakdown (GVB)-incompetent, displayed both PP1αand PP2A predominantly in the cytoplasm. By 15 days of age mouse oocytes, which are beginning to acquire OA sensitivity and GVB competence, showed a relocation of PP1αinto the nucleoplasm while PP2A remained predominantly cytoplasmic. This is the first specific identification of PP1αand PP2A in mouse oocytes. The differential localization of PP1αand PP2A, in addition to the relocation of PP1αduring the acquisition of meiotic competence, suggests that these PPs have distinct regulatory roles during the resumption of meiosis.